Dental casting apparatus



May 8, l923. 1,454,290

E. J. KOCHMIT DENTAL CASTING APPARATUS Filed Dec. 23 1921 5 Shees-Sheet i9 a? MUM yg I mw;

Patented May 8, 1923.

EDWARD 1'. KCHE/11T, 0F CLEVELAD, OHIO.

DENTAL CASTING APPARATUS.

Application ledl December 23, 1921. Serial No. 524,866.

To all w hom l may concern Be it known that I, EDWARD J. KocHMrr, citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Dental Casting Apparatus, of which the following is a speciication.

This invention is a dental casting apparatus in which porcelain and similar castings can be made, the apparatus involving a combined fusing and casting outfit, including an electric furnace for fusing and a suction apparatus for transferring the fused material to the mold, embodying the so-called vacuum method. Furthermore, the invention provides a combined fusing or casting furnace of relatively large size, and a smaller auxiliary muftle. furnace for baking or tintiug small work after casting, only one set of electrical connections being provided, and a single rheostat and pyrometer serving to cooperate with both furnaces or muffies. Also one action or operation can be performed in one of the furnace chambers while another is bein performed in the other, thereby saving t e expense of separate furnaces as well as considerable time for operations of different furnaces. improvements also appear in the details of the casting apparatus, as Will be more fully apparent from the following description.

In the accompanying drawings, Fig. 1 is a plan view of the apparatus, parts being broken away. Fig. 2 is a section on the line 2 2 of Fig. 1, parts being shown in elevation. Fig. 3 is a section on the line 3-3 of Fig. 1. Fig. 1 is a fragmentary horizontal section through the auxiliary furnace with the door removed. Fig. 5 is a wiring diagram. Fig. 6 is a plan view of the mold base. Fig. 7 is a plan of the casting furnace pan or plate. Fig. 8 is an edge view of Fig. 7. Fig. 9 is a vertical section of a modified mold. Fig. 10 is a vertical sectional view illustrating a method of building a mold, the mold being inverted.

In the drawings, 1 indicates a furnace casing having a top cover 2, and an end cover 3, the latter being provided with an opening 4 into the small or auxiliary furnace. BeloW the door is an outer shelf 5 mounted on the end cover. Within the casing thus formed -is a lining 6 of asbestos or other Suitable material, having cavities to receive the tire clay muiie 7 for casting or fusing large work and the lire clay muie 21 for fusing or tinting small work. The muille 7 rests on a bed 7a formed in the lining 6, and has an upper chamber 8 and a lower chamber 9, with an annular shoulder 10 at the top of the lower' chamber, this shoulder having diametrically opposite notches 11. 12 is' a doorway opening out of the chamber 8, and this may be' closed by a fire clay door 12B mounted on a shelf 15.

l'n the wall of the mufle 7 is a platinum resistance wire 16 Wound in grooves, said wire being lightly covered with a suitable coating, and 17 and 18 are contact studs connected to opposite ends of this wire and provided with binding posts 19 and 20. The small muiile 21 contains a chamber 22 and a door 23 resting on the shelf 5, and 24: indicates a platinum resistance wire wound in a spiral groove in the wall of the chamber 22, and having a suitable covering. Contact studs 25 and 26 are connected to opposite ends of the wire 24 and are provided with binding posts 27 and 28. A rheostat 29 is connected in the circuit of the respective muiiles, and stands on an insulated base 30 of marble or similar material, this base resting on the vacuum tank 31 which is provided with a pump 32, the handle of which is indicated at 83, for exhausting the air from the tanlr 31. 81 is a vacuum gauge connected to the tank. A pipe 35 leads from the vacuum tank to the base of the casting furnace, and is provided with a hand valve 36 and a coupling 237. 38 is the mold or matrix base having an externally threaded stem 39 extending through the bottom of the furnace and allowing the mold 40 to bc connected to the pipi` 35 by means of the coupling 87, the stem 2&9 having a hole 39 through theI same. The upper face of the base 38 has grooves 4l loading to the hole 39 in the stem :39. and said base has an upstanding flange 42 which is threaded internally to receive an externall)Y threaded sprue ring 48, which has lugs llprojecting from the top thereof and adapted to rest in the notches 11 in the shoulder l0. whereby the mold is held in position. The stem 39 extends through a hole l5 in the bottom of the furnace casing.

rlhe wiring includes supply wires 46 and 18 connected respectively to binding posts 47 and 49 ou the marble base, which is also provided with knife switches 50 and 51 conlUl-a trolling the circuit to the respective furnaces 7 and 2l and to the rlieostat the lever of which is indicated at 52, the contacts at 52, and the stops at 53, the furnace coils being arranged in parallel as shown in Fig. 5. A pyrometer is indicated at 54, supported by a bracket 54 on the base, and

pnovided with binding posts 55 and 56 connected to wires 57l and 58, with extension plugs 59 and 60 leading to the thermo-couple wires 63 which extend into the chamber 8 of the larger furnace, and 64 and 65 lare Wires connecting the pyroineter binding posts to extension plugs 66 and 67 whic lead t0 the thermo-couple wires 7() extending into the chamber 22 of the smaller furnace, 61 and 68 indicating supports for the pairs of pyrometer wires respectively, these suports being mounted on the cover 2 and casing 1 respectively.

The mold structure and method of building same are shown in Fig. 10. A metal cone shaped ring 71 is fitted in the top of the inverted mold ring 43, and this cone has a cavity 72 which receives the wax filler 73 for holding the pin 74 which supports the wax pattern 75 of a crown or inlay, said wax disappearing in the operation of c asting, as is well known, and the mold receives the bed 76 of silex, or similar material, as shown in Fig. 2, the pin 74 when withdrawn leavingl an ingate 77 to the mold cavity, and the porcelain or gold 78 to be molded resting in the cavity produced by the removal ot' the ring 71.

For baking work that is too large for the small mui'lle 21, the upper chamber 8 of the inuille 7 may be used, by removing the mold 40 and inserting the lire clay or platinum pan 71 which will be supported by the shelf 10 and will form a bottom for the chamber, the hole 45 being plugged to prevent the escape of heat.

For small castings the similar mold 40n shown in Fig. 9 may be used, this mold being of less diameter than the mold 40,

'and the projections 44a being longer to rest in the notches 11.

Referring to the wiring diagram in Fi 5, when the large furnace 7-is to be beate the switch is closed, the current flowing from the wire 46 through the rheostat 29, the switch, the resistance 16 and the return wire 48, the' switch 51 being opened. B closing the switch 51 and opening the switch 5() the small muflie 21 is heated; or t0 heat both furnaces simultaneously both switches are closed. The pyroineter is capable of use with either furnace.

The structure embodies combination casting and baking furnaces on one setting and a single set of adjuncts, which saves initial cost and permits either one or both Operations to be performed.

I claim:

l. A dental castin apparatus comprising a single casing, and llyarger and smaller electric furnaces enclosed in said casing, the larger furnace being provided with means to support a mold therein and with vacuum connections to said mold.

2. A dental casting apparatus com rising a single casing, and larger and smal er furnaces supported therein, one furnace having an opening through one wall of the casing and the other furnace having an opening through another wall of the casing, and the larger furnace being provided with means for supporting a mold therein and with vacuum casting connections to said mold.

3. A dental casting apparatus comprising a furnace having upper and lower chambers with a shoulder at the top of the lower chamber, a mold fitting in the lower chamber and having projections resting on said shoulder and a stein extending through the bottom of the chamber, and a vacuum pipe connected to said stem.

In testimon whereof, I aix my signature in presence o two witnesses.

EDWARD J. KOCHMIT. Witnesses JOHN A. BOMMHARDT, Bassin F. POLLAK. 

